AI Hints and Restrictions

Every building’s init.lua file has an aihints table in its new_<building_type>_type{table} function. This aihints table can contain any number of entries, which will help the AI decide when and where to build or dismantle a building of that type and/or how to treat it.

All entries in aihints are optional.


The AI has separate code paths for various building categories. Many of them are categories that contain one unique building (ranger, well, port, fish breeder, barracks and so on), and these cannot be combined with other types of buildings and are mostly mandatory.

The main categories where you can freely modify and add buildings are:

  • Military sites

  • Training sites

  • Pure production sites (they have outputs, and optionally inputs, but no production hints)

  • Pure supporters (they have production hints, but neither inputs nor outputs)

  • A combination of supporter and production site is possible, but suboptimal

You can create as many building types as you want in these main categories, but make sure that you don’t combine any incompatible features (for example, shipyard and mines don’t combine).

With the exception of the barracks and the building that produces carrier2 (see: Configuring a Tribe’s Units Usage), production of workers in production sites is not supported at this time.

Common Building Hints


The amount of this building to be built while establishing a basic economy, e.g.:

basic_amount = 1,

If a building of this type hasn’t been built already, force that a building of this type will be constructed after the given time (in seconds) has elapsed, e.g.:

forced_after = 890,

Note: forced after can interfere with setting up the basic economy defined by basic_amount: if we don’t want the building to be part of the basic economy but it is forced before all the buildings for the basic economy have been built, this can lead to unobvious behavior. Part of this ambiguity is due to the genetic algorithm.


Do not build this building before the given time (in seconds) has elapsed, e.g.:

prohibited_till = 1500,

This takes precedence over basic_amount, so it means it can delay achieving the basic economy.


The maximum number of this building type that the very weak AI is allowed to build, e.g.:

very_weak_ai_limit = 1,

The maximum number of this building type that the weak AI is allowed to build, e.g.:

weak_ai_limit_ = 2,

Military Sites


The building will be used by the AI for expanding the territory, e.g.:

expansion = true,

Note: It is recommended to have at least one building has this feature.


The building is suitable for military conflicts, e.g.:

fighting = true,

Note: It is recommended to have at least one building has this feature.


Prefer this type of military site near mountains, e.g.:

mountain_conqueror = true,

Note: It is recommended to have at least one building has this feature.

Production Sites


DEPRECATED The building will generate this ware from the map, e.g. a well mining the water ware, or the hunter returning from the hunt with the meat ware. The same ware needs also to be listed as the first one of the building’s outputs, e.g.:

aihints = {
    collects_ware_from_map = "meat"

outputs = {

Note: The AI expects exactly one such building type for each of the following wares: fish (fisher), granite (quarry), log (lumberjack/woodcutter), meat (hunter), water (well).


DEPRECATED The building will mine to obtain the given ware, e.g.:

mines = "resource_gold",

DEPRECATED The percentage that a mine will mine of its resource before it needs enhancing, e.g.:

mines_percent = 60,

The building needs to be placed near a body of water, e.g.:

needs_water = true,

Note: The AI expects exactly one such building type.


The building will recruit the tribe’s carrier2, for example oxen or horses, e.g.:

recruitment = true,

This building will construct ships, e.g.:

shipyard = true,

Note: The AI expects exactly one such building type.


This building is needed for expedition and seafaring, e.g.:

supports_seafaring = true,

The building needs a lot of space around it, for example a farm needs space for its fields, e.g.:

space_consumer = true,

DEPRECATED This building will support the production of the given wares without producing it directly, e.g.:

supports_production_of = { "fish" },

For example, if a building supports the production of fish, it should be placed near a building that has fish in its output.

Note: The AI expects that supporters will have no inputs and no outputs. Although the AI can tolerate such buildings, they will be primarily treated as normal production sites when deciding on the building’s location.


This building will be built only if a supporter is nearby:

requires_supporters = true,

For example if set for a Frisian aqua farm, it will be built only if a clay pit producing the

ponds is nearby.

Note: This hint shouldn’t be used for lumberjacks due to internal AI mechanics


The maximum percengate this training site will have among all training sites, e.g.:

trainingsites_max_percent = 20,

In this example, if an AI has built 5 training sites, it will have a maximum of 1 site of this type. If it has built 10 training sites, the maximum is 2. For training sites that don’t have this value set, their percentage will be distributed evenly.